Management of whitefly this season will be challenging as a result of the high rainfall and flooding in November and again in February which has resulted in a wide spread of crop maturity both between and within each region. While some cotton crops will mature on time, others could be set back by as much as six weeks by the cool… Read more »
As the earlier plantings of sorghum progress through flowering, moderate to high Helicoverpa pressure means that many crops have caterpillar numbers over threshold. Nucleopolyhedrovirus (NPV) is one of the main insecticides used to control Helicoverpa larvae in sorghum, however prevailing conditions play an important role in the speed and level of control achieved with NPV.
As the cotton season gets underway aphids are starting to be detected in crops, on ratoons, volunteers and weeds. Last season, there were some regions where Cotton Bunchy Top (CBT) was detected in crops towards the end of the season. To assess and manage the risk of yield loss caused by CBT, and minimise the difficulties of controlling insecticide resistant… Read more »
Last season was a somewhat low pressure year for silverleaf whitefly (SLW) in all cotton districts. The low pressure may have been attributed in part to high rainfall especially through central Queensland which does not favour whitefly population build up. St George and Mungindi districts still reached densities that exceeded the recommended insecticide spray thresholds although they generally fitted into… Read more »
As winter crops finish up and approach harvest, there are a couple of pests that still have the potential to cause some concerns. Armyworm and helicoverpa in barley, wheat and oats. There have been a number of reports of armyworm activity across the northern region in isolated pockets. Armyworm has the capacity to lop heads in barley, wheat and oats… Read more »
The wet spring, early summer conditions have favoured the return of a pest not seen for many years – slugs! Damaging slug populations, reported in seedling crops in northern NSW and southern Queensland, have totally destroyed some pulse crops. Increased slug activity may also be due to the increase in zero/minimum till and stubble retention practices which favour slug and… Read more »
Helicoverpa populations have started with a bang this season. One or more larvae per plant are common in pre-flowering sorghum, corn and cotton. However, early flowering sorghum crops are carrying up to 10 larvae per head. Corn and sorghum (monocot crops) host only Helicoverpa armigera, not H. punctigera – which has implications for control. Some key issues relevant to dealing… Read more »
In order to keep you updated with entomology activities, the following article outlines the research trials to be conducted on mirids this season on the Darling Downs by Dr Moazzem Khan (Senior Entomologist, DEEDI, Toowoomba).
With some chickpea crops being sprayed out, rather than harvested, there are reports of helicoverpa larvae surviving on crop residues. The survival of larvae, particularly large late instar larvae, poses a threat to subsequent crops that may be sown directly into the chickpea residues. It is important to check for surviving larvae under the chickpea residues before the next crop… Read more »
This winter we’ve seen several instances of severe scarab damage to winter cereals (wheat, barley and oats) , including on crops at Jandowae and Felton on the Darling Downs. The photograph below shows that severe damage is mostly confined to areas of paddocks which were previously pasture – and this is where the highest scarab populations were found.
